Piston ring



May 12, 1959 M. w. MARIEN 3 i I PISTONRING Original Filed Aug. 9, 1952United States Patent 2,886,383 PISTON RING Melvin W. Marien, Brentwood,Mo., assignor to Ramsey Corporation, St. Louis, Mo., a corporation ofOhio Application May 2, 1956, Serial No. 582,229, now Patent No.2,831,738, dated April 22, 1958, which is a division of applicationSerial No. 303,465, August 9, 1952, now Patent No. 2,744,803, dated May8, 1956. Divided and this application March 14, 1958, Serial No. 721,443

4 Claims. (Cl. 309-45) This invention relates to packing ring assemblieshaving cylinder wall engaging rings held in operative position by acombination expander and spacer ring. Specifically, this invention dealswith an oil control piston ring assembly having top and bottom flat thinring segments or rails and a self-expanding open-type ring between andbehind the thin rings or rails to space and exp and the thin rings orrails.

The present application is a division of my copending application SerialNo. 582,229, filed May 2, 1956, now

Patent No. 2,831,738, which, in turn, is a division of my US. Patent No.2,744,803, granted May 8, 1956, from an application filed August 9,1952.

This invention will hereinafter be specifically described as embodied ina piston ring assembly for pistons of internal combustion engines but itshould be understood that the ring assemblies of this invention aregenerally useful as packing rings to control lubrication of relativelymovable parts.

According to this invention, there is provided a stack of ringsincluding top and bottom fiat thin steel rail segments and anintermediate combination expander and spacer ring. This intermediatering extends between and behind the steel rings or rails and is aradially compressible self-expanding flexible sheet metal ring adaptedto exert equal expansion loads around the entire circumference of eachof the thin rings or rails. These rail rings or segments are preferablyprovided with chromiumplated outer rounded peripheries to present hardwearresisting edges to the cylinder wall. The expander and spacer ringis preferably formed of thin steel strip stock and is spring tempered.This combination expander and spacer ring is corrugated axially toprovide segment or rail rings supporting top and bottom loops or crownsjoined by sloping legs. Tab portions are formed on the inner peripheralends of the legs and project beyond the top and bottom loops or crownsto provide abutment shoulders at the inner ends of the legs for engagingthe inner peripheries of the segment or rail rings supported by theloops or crowns. When the combination spacer and expander ring iscircumferentially compressed, as when assembled in a piston ring groove,the portions of the tabs projecting beyond the legs will engage theinner peripheries of the rails or segments supported by the loops orcrownsto radially expand these rails or segments against the wall of thecylinder in which the piston reciprocates. The arrangement is such thatthe stack of rings does not bottom on the inner end of the piston ringgroove, and the outer peripheries of the rails extend beyond the outerperiphery of the corrugated ring. The assembly has open spacestherethrough adapted to communicate with oil vent holes in the pistonfor controlling drainage of oil between the thin ring segments or rails.

An important feature of this invention resides in the provision of asingle ring having the dual capacity of supporting the ring segments orrails in spaced operative position while at the same time radiallyexpanding these rings" against the cylinder wall.

of pistons wherein a single spring ring-acts as an expander and aspacer.

A still further object of the invention is to provide an oil controlring for internal combustion engine pistons wherein a one-piece radiallyexpansible ring supports a plurality of sealing rings in spacedoperative relation.

A further object of this invention is to provide an oil control ring forthe oil grooves of internal combustion engine pistons which has a pairof spaced-opposed thin flat steel segment rings with outer peripheraledges having a hard wearable chromium plating thereon and with a springmetal corrugated ring extending between and behind the thin rings tosupport the same against the top and bottom side walls of the ringgroove to seat their hard outer edges on a cylinder wall receiving thepiston.

A specific object of this invention is to provide an axially corrugatedcombination spacer and expander piston ring having top and bottom railring supporting loops or crowns connected by inclined legs and havingtabs on the inner peripheral ends of the legs projecting beyond the topsand bottoms of the loops or crowns to provide abutment shoulders forexpanding rail or segment rings supported on the loops or crowns.

Still another specific object of this invention is to provide a combinedspacer and expander piston ring formed from strip metal stock slitinwardly at intervals from one edge to provide cuts for forming theterminal ends of tabs and also slit parallel to this edge to providecuts intersecting the slits and then corrugated to provide axiallyinclined legs and top and bottom rail rings supporting loops with thetabs remaining fiat and extending beyond the loops at the innerperiphery of the ring.

Other and further objects of this invention will become apparent tothose skilled in the art from the following detailed description of theannexed sheet of drawings which, by way of a preferred example,illustrates an em-- 'bodiment of this invention.

On the drawing:

Fig. 1 is a side elevational view of a piston equipped for the oilcontrol piston ring assembly.

Fig. 5 is an enlarged fragmentary side elevational view of the ring ofFig. 4.

Fig. 6 is a cross-sectional view of the ring of Fig. 5 taken along theline VI-VI of Fig. 5.

Fig. 7 is a fragmentary plan view of a blank from which the ring ofFigs. 4 to 6 is formed.

As shown on the drawing:

In Figs. 1 and 2 the reference numeral 10 designates generally a piston'for an internal combustion engine.

The piston 10 is equipped with the conventional top ring groove 11,middle ring groove 12, and oil ring groove 13. A conventional splitsolid cast iron piston ring 14 is mounted in the top groove 11 toprovide a compression seal. A conventional split compression ring 15also of cast iron composition is seated in the middle groove 12. Therings 14 and 15 have broad cylinder wall engaging faces 14a and 15arespectively.

The oil ring groove 13 is wider than the grooves l1 and 12 and is joinedthrough oil holes such as 16 with the interior of the piston. Thisgroove 13 has a top wall 13a and a bottom wall 13b extending radiallyoutward from a vertical back wall 130 which is pierced at intervals bythe oil holes 16.

An oil control ring assembly 17 of this invention is mounted in the oilgroove 13. This assembly 17 includes a top thin flat ring segment 18, anidentical bottom seg ment 19, and an intermediate combination expanderand spacer ring 40. The rings 18 and 19 have rounded outer peripheraledges 18a and 1% each covered with a layer of chromium or other hardcorrosion and wear-resisting metal 21 so that the cylinder wall engagingedges of each ring are reinforced with a hard coating. The coating canbe applied by electroplating, brazing, or in any other suitable manner.The inner peripheral edges of the rings 18 and 19 are also rounded at1819 and 1%, respectively, but the inner peripheries are not coated withthe hard metal. As shown in Fig. 3, the ring segments or rails 18 and T9are split and gaps 22 and 23 are respectively provided between the endsof the ring. These gaps will vary in width as shown, even when the ringsare in operation on the piston 10 as shown in Fig. l to permit radialcontraction and expansion of the thin rings.

The ring 49, on the other hand, has abutted together ends 41 as shown inFigs. 3 and 4, providing a closed ring, which, when radially compressed,will contract with a resilient spring-like action to exert an equalouter radial load around its entire periphery.

The ring 49 is provided with corrugations extending in a vertical planeand having the abutting ends 41 providing a closed ring. Thecorrugations or convolutions, as best shown in Figs. 3 and 5, includelegs 40a sloping in a vertical plane and connected at their top andbottom ends by loops or crowns 40b. The legs 49:: and the loops 40bextend radially of the ring groove from tab portions 400, formed on theinner peripheral ends of the legs 40a and projecting beyond the top andbottom of the loops 40b to provide shoulders 40d at the inner ends ofthe legs, which shoulders project above and below the loops. Theseshoulders 400? form abutments for the inner edges of the ring segments18 and 19, as shown in Fig. 2, while the legs 40a extend between therings 18 and 19 to form separators with the rings resting on the loops40b.

As shown in Fig. 7, the ring 40 is formed from flat strip stock 42 whichis slit inwardly from one edge at intervals to provide cuts 43 formingthe terminal ends for the tabs 400. The strip is also slit parallel toan edge to provide cuts 44 which intersect the cuts 43 and, therefore,separate the outer ends of the tabs from the loops. The strip is thencorrugated to provide the legs 40a and the connecting loops 40b whilethe tab blank portions 45 remain flat.

Therefore, vertical corrugations are provided in the ring 40 to form topand bottom rail ring supporting loops or crowns and inclined legs, whileabutment shoulders are formed from the tabs on the inner periphery ofthe mug.

Thus, the ring 40 exerts its expanding load simultaneously on both thinrings 18 and 19, and at the same time, separates these rings to holdthem against the top and bottom faces of the ring groove.

The corrugations or legs 40a are separated around the periphery of thering 40 so that the space between the rings 18 and 19 is inopencommunication with oil drain holes such as 16 communicating with theback wall 13c of the ring groove.

The ring groove 13 can be of any desired depth since the-ring 40 neednot be bottomed on the groove in order to exert its expanding force.Thus, as shown in Fig. 2, the inner periphery of the ring 40 is actuallyspaced radialt ly outward from the back wall of the ring groove 13. Yet,the ring by being under inherent radial compressive load will exert itsexpanding force on the ring segments 18 and 19.

From the above description it will, therefore, be understood that thisinvention provides a packing ring assembly wherein sealing rings areurged radially outward and are held in separated relation by aself-expanding spring ring which does not depend upon engagement with aring groove to exert its expanding force on the sealing rings. Theselfexpanding ring thus serves a dual function of an expander and aseparator in a packing ring assembly. The combination expanding andseparator ring is open around its periphery so as not to impede freedrainage of oil in oil ring assemblies. The ring can be made continuousby welding or otherwise securing the ends together and the resultingcomplete annulus can be stretched over the head of the piston andsnapped into the oil ring groove.

I claim as my invention:

1. A combined spacer and expansion ring for packing ring assemblieswhich comprises an axially corrugated spring metal ring having slopinglegs connected at the tops and bottoms thereof by loops, said loopshaving slits parallel to the inner periphery of the ring, cuts bisectingsaid slits and extending to the inner periphery of the ring, said slitsand cuts defining tabs connected to the inner peripheries of the legsand said tabs extending beyond the loops to form abutment shoulders atthe inner peripheries of the loops, said ring adapted to be radiallycontracted through the resiliency of the corrugations for causing theabutment shoulders to exert a radially expanding force on ringssupported by the loops.

2. A spacer and expander for supporting, spacing and outwardly pressinggenerally flat parted thin rails in a piston ring assembly comprising agenerally circular corrugated length of fiat metal ribbon stock havingabutting ends and substantially parallel longitudinal edges, thecorrugations extending generally axially and comprising up per and lowerradially extending crowns connected alternately at their ends by axiallyinclined legs, and upstanding narrow tabs on the inner ends of the legsextending beyond the crowns to provide abutment shoulders for outwardlypressing the rails of the assembly, said tabs being inclined axiallywith the legs and the projecting ends of the tabs converging toward thecentral portions of the crowns to provide two abutment shoulders foreach crown.

3. A piston ring assembly comprising a pair of cylinder engaging railsand a combined spacer and expander member for expanding the railsradially and for holding the rails in axially spaced relation, saidmember comprising a strip of sheet metal corrugated axially to provide atop series of crowns and a bottom series of crowns, the crowns of thetwo series alternating with respect to each other and being concentric,upright legs connecting the ends of the two series of crowns, and tabson the inner peripheries of the legs extending axially beyond the crownsto provide abutment shoulders on each crown adapted to engage the railssupported on the crowns for expanding the rails radially while thecrowns support the rails in axially spaced relation.

4. A combined spacer and expander piston ring composed of a ribbon ofsheet metal having first slits inwardly from one edge at intervals andsecond slits parallel to said edge intersecting the first slits, saidribbon having axial and circumferential corrugations defining alternatetop and bottom loops joined by inclined legs and tabs provided by theslit portions on the inner periphery of the legs extending parallel withthe legs above and inelow the loops to form converging abutments on eachoop.

References Cited in the file of this patent UNITED STATES PATENTS2,656,230 Phillips Oct. 20, 1953

